This invention relates to the field of vehicle frames and more specifically to frames for vehicles of various lengths. Many vehicles are produced in a progressive series of sizes, requiring frames of various lengths. This requires the production and inventorying of frames of various sizes. Also some vehicles used to support heavy loads at one end, such as fork lift trucks, and vehicles which pull heavy loads, such as tractors, require counterbalancing by supporting a counterweight on the other end of the vehicle a selected distance from the axles. Such vehicles thus require auxiliary frame means for extending one end of the vehicle for extended support of the counterweight to achieve a required moment arm for counterbalancing of the vehicle.